1. Technical Field of the Invention
The present invention relates to a composition in the form of an emulsion comprising a mineral (inorganic) oxide and an oligomer or a polymer derived from a polyolefin, especially in the form of a water-in-oil emulsion, and to the use of said composition, especially in the cosmetics field, in particular for antisun care and/or protection of the skin, the lips and the hair.
2. Description of Background/Related/Prior Art
It is common practice in the cosmetics field to use chemical screening agents to obtain antisun products. These chemical screening agents may be introduced fairly readily into emulsions by dispersion in the oily or aqueous phase of the emulsion, depending on their lipophilic or hydrophilic nature.
To obtain high protection factors, it is necessary to increase the content of chemical screening agents. However, for reasons of tolerance, it is sought to avoid using an excessively high level of chemical screening agents, and it is preferred to introduce, alongside or in place of the chemical screening agents, mineral physical blocking agents, in particular metal oxides such as, for example, titanium dioxide and zinc oxide, which offer excellent anti-UV properties and very good skin tolerability.
However, introducing these metal oxides poses problems of cosmetic acceptability. Specifically, the antisun products containing them are often in the form of relatively thick emulsions, which are difficult to apply and to spread, heavy and sticky. In addition, with certain mineral blocking agents, for instance titanium dioxide, these defects are accompanied by a whitening effect during spreading on the skin.
Moreover, it is sought to obtain antisun emulsions that have a fluid texture, since the fluid texture makes them more practicable, easier to apply and more pleasant to use. However, fluid emulsions are also more difficult to produce with mineral blocking agents, since metal oxides have the drawback of destabilizing the emulsions into which it is desired to introduce them, and especially when they are very fluid emulsions. This difficulty of introducing metal oxides is even greater when the oxide content exceeds 1% of the final composition.
The instability phenomena are reflected in particular by the aggregation of the solid particles, the creaming and sedimentation of the emulsions, a heterogeneous appearance of the emulsions, and a change in the texture over time, this change being reflected by a thickening of the texture, which also becomes granular and heterogeneous.